Brain adipocytokine action and metabolic regulation

Weight Regain after Metabolic Surgery: Beyond the Surgical Failure

Patients undergoing metabolic surgery have factors ranging from anatomo-surgical, endocrine metabolic, eating patterns and physical activity, mental health and psychological factors. Some of the latter can explain the possible pathophysiological neuroendocrine, metabolic, and adaptive mechanisms that cause the high prevalence of weight regain in postbariatric patients. Even metabolic surgery has proven to be effective in reducing excess weight in patients with obesity; some of them regain weight after this intervention. In this vein, several studies have been conducted to search factors and mechanisms involved in weight regain, to stablish strategies to manage this complication by combining metabolic surgery with either lifestyle changes, behavioral therapies, pharmacotherapy, endoscopic interventions, or finally, surgical revision. The aim of this revision is to describe certain aspects and mechanisms behind weight regain after metabolic surgery, along with preventive and therapeutic strategies for this complication.

Adiponectin Modulates Smooth Muscle Cell Morpho-Functional Properties in Murine Gastric Fundus via Sphingosine Kinase 2 Activation

Adipokines are peptide hormones produced by the adipose tissue involved in several biological functions. Among adipokines, adiponectin (ADPN) has antidiabetic and anti-inflammatory properties. It can also modulate food intake at central and peripheral levels, acting on hypothalamus and facilitating gastric relaxation. ADPN exerts its action interacting with two distinct membrane receptors and triggering some well-defined signaling cascades. The ceramidase activity of ADPN receptor has been reported in many tissues: it converts ceramide into sphingosine. In turn, sphingosine kinase (SK) phosphorylates it into sphingosine-1 phosphate (S1P), a crucial mediator of many cellular processes including contractility. Using a multidisciplinary approach that combined biochemical, electrophysiological and morphological investigations, we explored for the first time the possible role of S1P metabolism in mediating ADPN effects on the murine gastric fundus muscle layer. By using a specific pharmacological inhibitor of SK2, we showed that ADPN affects smooth muscle cell membrane properties and contractile machinery via SK2 activation in gastric fundus, adding a piece of knowledge to the action mechanisms of this hormone. These findings help to identify ADPN and its receptors as new therapeutic targets or as possible prognostic markers for diseases with altered energy balance and for pathologies with fat mass content alterations.

Garcinia gummi-gutta: Phytochemicals and pharmacological applications

Garcinia gummi-gutta, also known as Garcinia cambogia, is a member of the Guttiferae family. Garcinia is a polygamous genus consisting 200 species of trees and shrubs. It is found in different zones of the planet including Asia's tropical regions. In India alone, around 30 species have been discovered. They are widely used as a flavoring agent to garnish fish curry in southern India, particularly in Kerala and Karnataka. The fruit rind of G. gummi-gutta has traditionally been used to treat gastrointestinal problems, diarrhea, and ulcers. South Indian people have been utilizing it traditionally as evidenced by its ethnobotanical properties. In vivo and in vitro effects of the crude fruit extract showed anti-inflammatory, anti-cancer, anthelmintic, anti-microbial, and antioxidant activities. G. gummi-gutta fruit rind is medicinally significant and is frequently used in ayurvedic and traditional medicine for many diseases. Various secondary metabolites such as organic acids-hydroxycitric acid (HCA), flavonoids, terpenes, polysaccharides and polyisoprenylated benzophenones-garcinol, xanthochymol, guttiferone, benzophenone, xanthone, biflavonoids, alkaloids, tannins, phenols, and saponins isolated from the G. gummi-gutta have diverse pharmacological activities. This review provides a summary of G. gummi-gutta, including its biological activities, phytochemistry, and ethnobotanical applications.

A transdermal treatment with MC903 ameliorates diet-induced obesity by reducing visceral fat and increasing myofiber thickness and energy consumption in mice

AIM

MC903 is a synthetic derivative of vitamin D3 that has been designed to diminish its impact on calcium metabolism and is clinically used as a transdermal reagent for psoriasis. Animal studies showed that an oral or intraperitoneal vitamin D3 treatment prevented the development of obesity. In contrast, the bioavailability of orally administered vitamin D3 is reported to be low in obese patients. In the current study, we aimed to investigate the impact of a transdermal treatment with MC903 in established obese mice. We further studied the underlying mechanisms of MC903-mediated metabolic improvement.

MATERIALS AND METHODS

Male C57BL/6 J mice were fed standard chow or a 60% high-fat diet (HFD) for 7 weeks, and a transdermal treatment with MC903 on the ear auricle was initiated thereafter. The metabolic profiles of mice were analyzed during 4 weeks of treatment, and mice were dissected for histological and gene expression analyses. The direct impacts of MC903 and vitamin D3 were investigated using 3T3-L1 adipocytes and C2C12 myotubes in vitro.

RESULTS

HFD-fed mice showed significant increases in body and epididymal white adipose tissue (eWAT) weights with enlarged adipocytes. They exhibited glucose intolerance, decreased oxygen consumption, and chronic inflammation in eWAT. The transdermal treatment with MC903 significantly ameliorated these metabolic abnormalities in HFD-fed mice without affecting food consumption. In accordance with enhanced energy metabolism, myofiber diameters and the expression of uncoupling protein 3 (UCP3) in the gastrocnemius and soleus muscle were significantly increased in MC903-treated HFD mice. In addition, vitamin D3 and MC903 both suppressed adipogenic differentiation and enhanced lipolysis in 3T3-L1 adipocytes, and increased UCP3 expression in cultured C2C12 myotubes. Furthermore, MC903 increased oxygen consumption and UCP3 knockdown significantly decreased them in C2C12 myotubes.

CONCLUSIONS

A transdermal treatment with MC903 increased myofiber diameter and energy metabolism and decreased visceral fat accumulation, thereby improving obesity and glucose intolerance in mice.

Adipokines: Deciphering the cardiovascular signature of adipose tissue

Obesity and hypertension are intimately linked due to the various ways that the important cell types such as vascular smooth muscle cells (VSMC), endothelial cells (EC), immune cells, and adipocytes, communicate with one another to contribute to these two pathologies. Adipose tissue is a very dynamic organ comprised primarily of adipocytes, which are well known for their role in energy storage. More recently adipose tissue has been recognized as the largest endocrine organ because of its ability to produce a vast number of signaling molecules called adipokines. These signaling molecules stimulate specific types of cells or tissues with many adipokines acting as indicators of adipocyte healthy function, such as adiponectin, omentin, and FGF21, which show anti-inflammatory or cardioprotective effects, acting as regulators of healthy physiological function. Others, like visfatin, chemerin, resistin, and leptin are often altered during pathophysiological circumstances like obesity and lipodystrophy, demonstrating negative cardiovascular outcomes when produced in excess. This review aims to explore the role of adipocytes and their derived products as well as the impacts of these adipokines on blood pressure regulation and cardiovascular homeostasis.

CTRP3 as a novel biomarker in the plasma of Saudi children with autism

BACKGROUND

C1q/tumor necrosis factor-related protein-3 (CTRP3) has diverse functions: anti-inflammation, metabolic regulation, and protection against endothelial dysfunction.

METHODS

The plasma level of CTRP3 in autistic patients (n = 32) was compared to that in controls (n = 37) using ELISA.

RESULTS

CTRP3 was higher (24.7% with P < 0.05) in autistic patients than in controls. No association was observed between CTRP3 and the severity of the disorder using the Childhood Autism Rating Scale (CARS). A positive correlation between CARs and the age of patients was reported. Receiver operating characteristic (ROC) analysis demonstrated a low area under the curve (AUC) for all patients (0.636). Low AUCs were also found in the case of severe patients (0.659) compared to controls, but both values were statistically significant (P ≤ 0.05). Despite the small sample size, we are the first to find an association between CTRP3 and autism spectrum disorder (ASD).

Effects and mechanisms of CTRP3 overexpression in secondary brain injury following intracerebral hemorrhage in rats

C1q/TNF-related protein-3 (CTRP3) is a novel adipokine that serves an important role in oxidative stress, anti-apoptosis, anti-inflammation and immune regulation. The aim of the present study was to investigate the protective role of CTRP3 against intracerebral hemorrhage (ICH)-induced brain injury. A model of autologous arterial blood-induced ICH was constructed in rats. Intracerebral infusion of a lentivirus carrying the CTRP3 gene was used to induce CTRP3 overexpression in the brain. The effects and mechanisms of CTRP3 overexpression on brain injury were investigated by detecting brain edema, blood-brain barrier (BBB) integrity, neurological function and inflammatory-associated factors 3 days after ICH. The present results demonstrated that CTRP3 overexpression ameliorated ICH-induced neurological dysfunction, decreased brain edema, maintained BBB integrity and attenuated inflammation. The protective effect of CTRP3 overexpression was associated with increased activation of silent information regulator 1 (SIRT1). In conclusion, the present study demonstrated that CTRP3 overexpression protected against ICH-induced brain injury in rats, potentially via activating the SIRT1 signaling pathway.

The Association Between Three Adipocytokines (Adiponectin, Resistin and Visfatin) And Thyroid Status in Patients With Type 2 Diabetes Mellitus and Autoimmune Thyroiditis

Autoimmune thyroiditis (AIT) and type 2 diabetes mellitus (DM2) are the most common endocrinological diseases worldwide. Relation between these diseases explains several hypotheses. One of them is influence of some adipocytokines. This study evaluated association between three adipocytokines (adiponectin, resistin and visfatin) and thyroid and glycid status in patients with DM2 and AIT compared to the control group (CG). The group consisted of four subgroups: patients with DM2 without thyreopathies, patients with AIT on substitution therapy without diabetes and prediabetes, patients with DM2 and AIT on substitution therapy and healthy subjects as the CG. We investigated parameters of thyroid and glucose metabolism and serum levels of three adipocytokines. The mean level of resistin in the group of patients with diabetes and thyroiditis was significantly higher than in patients with thyroiditis without diabetes and than in the CG. We found a weak negative correlation between visfatin and fasting glucose levels in patients with thyroiditis without diabetes. We detected a weak negative correlation between resistin and glycated haemoglobin and a weak negative correlation between visfatin and thyroid gland volume in patients with diabetes without thyroiditis. In the CG we determined a weak positive correlation between visfatin and free thyroxin. Our results are consistent with several studies, which confirmed association between AIT and adipocytokines.

Clozapine Worsens Glucose Intolerance, Nonalcoholic Fatty Liver Disease, Kidney Damage, and Retinal Injury and Increases Renal Reactive Oxygen Species Production and Chromium Loss in Obese Mice

Clozapine is widely employed in the treatment of schizophrenia. Compared with that of atypical first-generation antipsychotics, atypical second-generation antipsychotics such as clozapine have less severe side effects and may positively affect obesity and blood glucose level. However, no systematic study of clozapine’s adverse metabolic effects—such as changes in kidney and liver function, body weight, glucose and triglyceride levels, and retinopathy—was conducted. This research investigated how clozapine affects weight, the bodily distribution of chromium, liver damage, fatty liver scores, glucose homeostasis, renal impairment, and retinopathy in mice fed a high fat diet (HFD). We discovered that obese mice treated with clozapine gained more weight and had greater kidney, liver, and retroperitoneal and epididymal fat pad masses; higher daily food efficiency; higher serum or hepatic triglyceride, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine levels; and higher hepatic lipid regulation marker expression than did the HFD-fed control mice. Furthermore, the clozapine group mice exhibited insulin resistance, poorer insulin sensitivity, greater glucose intolerance, and less Akt phosphorylation; their GLUT4 expression was lower, they had renal damage, more reactive oxygen species, and IL-1 expression, and, finally, their levels of antioxidative enzymes (superoxide dismutase, glutathione peroxidase, and catalase) were lower. Moreover, clozapine reduced the thickness of retinal cell layers and increased iNOS and NF-κB expression; a net negative chromium balance occurred because more chromium was excreted through urine, and this influenced chromium mobilization, which did not help overcome the hyperglycemia. Our clozapine group had considerably higher fatty liver scores, which was supported by the findings of lowered adiponectin protein levels and increased FASN protein, PNPLA3 protein, FABP4 mRNA, and SREBP1 mRNA levels. We conclude that clozapine can worsen nonalcoholic fatty liver disease, diabetes, and kidney and retinal injury. Therefore, long-term administration of clozapine warrants higher attention.

Leptin Contributes to Neuropathic Pain via Extrasynaptic NMDAR-nNOS Activation

Leptin is an adipocytokine that is primarily secreted by white adipose tissue, and it contributes to the pathogenesis of neuropathic pain in collaboration with N-methyl-D-aspartate receptors (NMDARs). Functional NMDARs are a heteromeric complex that primarily comprise two NR1 subunits and two NR2 subunits. NR2A is preferentially located at synaptic sites, and NR2B is enriched at extrasynaptic sites. The roles of synaptic and extrasynaptic NMDARs in the contribution of leptin to neuropathic pain are not clear. The present study examined whether the important role of leptin in neuropathic pain was related to synaptic or extrasynaptic NMDARs. We used a rat model of spared nerve injury (SNI) and demonstrated that the intrathecal administration of the NR2A-selective antagonist NVP-AAM077 and the NR2B-selective antagonist Ro25-6981 prevented and reversed mechanical allodynia following SNI. Administration of exogenous leptin mimicked SNI-induced behavioral allodynia, which was also prevented by NVP-AAM077 and Ro25-6981. Mechanistic studies showed that leptin enhanced NR2B- but not NR2A-mediated currents in spinal lamina II neurons of naïve rats. Leptin also upregulated the expression of NR2B, which was blocked by the NR2B-selective antagonist Ro25-6981, in cultured dorsal root ganglion (DRG) neurons. Leptin enhanced neuronal nitric oxide synthase (nNOS) expression, which was also blocked by Ro25-6981, in cultured DRG cells. However, leptin did not change NR2A expression, and the NR2A-selective antagonist NVP-AAM077 had no effect on leptin-enhanced nNOS expression. Our data suggest an important cellular link between the spinal effects of leptin and the extrasynaptic NMDAR-nNOS-mediated cellular mechanism of neuropathic pain.

The influence of hypertensive environment on adipose tissue remodeling measured by fluorescence lifetime imaging in spontaneously hypertensive rats

There is a lack of information correlating low adiposity with hypertension experienced by Spontaneous Hypertensive Rats (SHR) or overweight and normotension in Wistar-Kyoto (WKY). We aimed to investigate this lipodystrophy phenomenon by measuring fluorescence lifetime (FLIM), optical redox ratio (ORR), serum levels of hypothalamic-pituitary-adrenal (HPA) and/or hypothalamic-pituitary-thyroid (HPT) hormones axes between Wistar, WKY and SHR before and after establishment of hypertension. Under high blood pressure, we evaluated serum adipokines. Brown adipose tissue was characterized as lower ORR and shorter FLIM compared to white adipose tissue. HPT axis showed a crucial role in the SHR adipose tissue configuration by attenuating whitening. The increased adiposity in WKY may act as a preventive agent for hypertension, since SHR, with low adiposity, establishes the disease. The hypertensive environment can highlight key adipokines that may result in new therapeutic approaches to the treatment of adiposity dysfunctions and hypertension.

The adipokines and inflammatory status in the era of pediatric obesity

INTRODUCTION

Obesity is associated with a chronic inflammation due to the deficiency in immune activity related to adipose tissue. A wide-spectrum of pro-inflammatory cytokines secreted by adipocytes play an important role in the assessment of obesity-associated inflammatory status. The aim of this study was to assess the relationship between IL and 1β, IL-6, TNF α, leptin, and inflammatory status in children with overweight/obesity.

MATERIAL AND METHODS

We performed a cross-sectional study on 193 children, admitted to a Pediatric Tertiary Hospital in Romania. The children were divided according to BMI into: the study group-91 children with overweight/obesity, and the control group-102 children with normal BMI. Demographic, anthropometric, and laboratory parameters including the serum levels of several adipokines (leptin, IL-1β, IL-6, and TNF α) were assessed in both groups.

RESULTS

Our findings revealed significantly higher values of leukocytes, lymphocytes, platelets, AST, and ALT, as well as for the lipid metabolism parameters including cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and CRP, in children with overweight/obesity. We found significantly higher levels of adipokines in the serum of children with overweight and obesity assessed for leptin, IL6, and TNF α (p = 0.0145/p < 0.0001/p = 0.004/), except for IL-1β serum levels.

CONCLUSIONS

Childhood overweight and/or obesity is associated with a systemic inflammatory status demonstrated by increased levels of CBC parameters. Pro-inflammatory adipokines are also an essential factor in obesity-related inflammatory status according to our findings that underlined the importance of increased serum levels of IL-6, TNF α, and leptin in pediatric patients with overweight/obesity. Clinically, CBC parameters along with adipokines might represent useful diagnostic tools for low-grade systemic inflammation in children with overweight or obesity.

Has the adipokine profile an influence on the catch-up growth type in small for gestational age infants?

Infants born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature, and metabolic alterations in later life. Moreover, the post-natal growth pattern of SGA infants may be an important contributor to health outcomes later in life, which can be influenced by adipokines. The aims of this study were to compare plasma adipokine profiles (leptin, adiponectin, vaspin, chemerin, and nephroblastoma overexpressed (NOV/CCN3)) among SGA newborns aged 3 months, with low, normal, or high catch-up, to search for potential differences between males and females and to analyze the evolution of several adipokines in plasma from SGA newborns between 3 and 24 months. This prospective, longitudinal study was addressed in SGA Caucasian subjects at Hospital Universitario de Álava-Txagorritxu. We observed that infants with fast catch-up showed significantly lower birth weight than the other two groups. As far as adipokines are concerned, they could have an influence on catch-up type because differences among the three experimental groups were found. It may be proposed that health prognoses in infants with slow and fast catch-up are opposite, not only in adulthood but also during their first months. Finally, adipokine evolution patterns during the first 24 months of age differ, depending on the adipokine, and 24-month-old males show lower levels of leptin, adiponectin, and omentin than females.

The effects of green tea on lipid metabolism and its potential applications for obesity and related metabolic disorders - An existing update

Obesity is one of the top global issues, which induces several serious health consequences both physically and mentally, such as type 2 diabetes, cardiovascular diseases, dyslipidemia, eating disorders, depression and stress. However, the effective therapy to prevent and treat obesity and overweight, up to now, cannot be found nowadays. Several methods/medicines namely diet control, energy balance, environmental changes, genetic and stem cell therapies, new drugs/chemicals have been extensively studied to enhance the ability to control bodyweight and prevent obesity. Of all the aforementioned methods, green tea, used as a daily beverage, has shown beneficial impacts for the health, especially its anti-obesity effects. Available evidence shows that green tea can interrupt lipid emulsification, reduce adipocyte differentiation, increase thermogenesis, and reduce food intake, thus green tea improves the systemic metabolism and decreases fat mass. Here, we highlight and sum up the update investigations of anti-obesity effect of green tea as well as discuss the potential application of them for preventing obesity and its related metabolic disorders.

Preoperative Serum Leptin Level Is Associated with Preoperative Pain Threshold and Postoperative Analgesic Consumption in Patients Undergoing Cesarean Section

OBJECTIVE

This study aimed to investigate the preoperative level of serum leptin in cesarean section (C-section) patients with and without acute labor pain and its association with postoperative analgesic consumption and preoperative pain threshold.

MATERIALS AND METHODS

Preoperative leptin levels, preoperative pain threshold, postoperative analgesic consumption in the first 24 h, and postoperative pain severity (visual analog scale (VAS) scores at 1, 2, 4, 6, 12, and 24 h postoperatively) in C-section patients with labor pain (emergency C-section; n = 21) and without labor pain (elective C-section; n = 25) were compared.

RESULTS

There were no significant differences between the groups regarding the demographic characteristics. Leptin levels, postoperative VAS scores, and analgesic consumption were significantly higher in the group with labor pain, while the preoperative pain threshold was lower. Serum leptin levels correlated negatively with pain threshold and positively with postoperative analgesic consumption. Multiple linear regression analyses in our study revealed that the preoperative leptin levels and having an emergency C-section independently affected the postoperative analgesic consumption and preoperative pain threshold, whereas their combined effects on these parameters were statistically not significant.

CONCLUSION

Preoperative levels of serum leptin were higher in C-section patients with labor pain than in those without labor pain, and increased serum leptin levels were associated with decreased preoperative pain threshold and increased postoperative analgesic consumption in our study population. Postoperative analgesic requirements may vary among patients, and their requirements might be predicted using preoperative indicators. Serum levels of leptin might be one such indicator and this warrants further studies with larger sample sizes.

Circulating levels of adipokines are altered in patients with temporal lobe epilepsy

OBJECTIVE

A persistent low-grade inflammatory state has been described in patients with temporal lobe epilepsy (TLE) in the interictal period. Adipokines are cytokines produced by the adipose tissue that can influence inflammatory response. The purpose of this study was to evaluate the plasma levels of adipokines in patients with TLE in comparison with controls. In addition, we sought to investigate whether the levels of adipokines were associated with clinical parameters in TLE.

METHODS

Forty patients with TLE and 40 controls were enrolled in this study. All participants were subjected to clinical assessment that included the Mini International Neuropsychiatric Interview (MINI) and the Hamilton Depression Rating Scale (HAM-D). Peripheral blood was drawn, and plasma levels of adipokines (adiponectin, leptin, and resistin) were measured by enzyme-linked immunoassay (ELISA).

RESULTS

People with TLE presented higher leptin and lower adiponectin and resistin levels in comparison with controls. The levels of these adipokines correlated negatively with illness length but not with other clinical parameters. In a binary logistic regression model, higher leptin and lower adiponectin levels remained as significant predictors of TLE diagnosis.

CONCLUSIONS

These results corroborate the view that TLE is a multisystemic condition associated with low-grade inflammation.

C1QTNF6 is overexpressed in gastric carcinoma and contributes to the proliferation and migration of gastric carcinoma cells

In the present study, proteins differentially expressed between gastric cancer tissue and para‑tumoral normal gastric tissues were screened, and the function of the highly expressed protein C1QTNF6 in gastric carcinoma was investigated. The differential expression of mRNAs extracted from the tumor and adjacent tissues was analyzed using GeneChip assay. An AGS si‑C1QTNF6 cell line was constructed using shRNA‑C1QTNF6 lentivirus. The cell invasion and migration ability of C1QTNF6‑knockdown cells were determined by Transwell chamber migration and wound healing assays, respectively. The effects of C1QTNF6 on AGS cell cycle distribution and apoptosis were detected using a FACScan flow cytometer. The results demonstrated that the expression of 109 genes was increased and the expression of 129 was decreased in tumor tissues. Among these genes, the C1QTNF6 gene was highly expressed in tumor tissues and the AGS7901 cell line. C1QTNF6‑knockdown decreased the cell growth, and the proliferative and migration ability, as well as increasing the apoptosis of gastric carcinoma cells. In addition, the number of AGS cells in the G2/M phase was significantly increased after 5 days of C1QTNF6‑shRNA lentivirus infection. The results of the present study indicated that C1QTNF6 serves an important role in the development of gastric carcinoma. C1QTNF6 is involved in promoting the proliferation and migration, and in reducing the apoptosis of gastric carcinoma cells. These results provided a potential therapeutic target for the treatment of gastric carcinoma.

What is the role of adipokines in myasthenia gravis?

Objective

Myasthenia gravis (MG) is a disease with autoimmune etiology. The main pathomechanism is related to the production of antibodies against nicotinic acetylcholine receptor. The present study is aimed to compare the serum level of adipokines in patients with MG with that in controls, as well as to study the relation of these levels with disease severity.

Patients and methods

Fifty patients with MG and 30 healthy individuals were enrolled in our study. Serum concentrations of select adipokines, namely adiponectin, leptin, omentin, visfatin, and resistin were measured.

Results

The results showed a significant increase in serum concentrations of adiponectin and resistin in the patients with MG compared with the controls.

Conclusion

Further studies are warranted to assess changes in adipokine concentration levels in patients with MG.

Modulation of Glucose Metabolism in Hippocampal Neurons by Adiponectin and Resistin

Obese individuals exhibit altered circulating levels of adipokines, the proteins secreted by adipose tissue to mediate tissue cross-talk and regulate appetite and energy expenditure. The effect of adipokines on neuronal glucose metabolism, however, remains largely unknown. Two adipokines produced in adipose tissue, adiponectin and resistin, can gain access to the central nervous system (CNS), and their levels in the cerebrospinal fluid (CSF) are altered in obesity. We hypothesized that dysregulated adipokines in the CNS may underlie the reported link between obesity and higher risk of neurological disorders like Alzheimer's disease (AD), by affecting glucose metabolism in hippocampal neurons. Using cultured primary rat hippocampal neurons and mouse hippocampus slices, we show that recombinant adiponectin and resistin, at a concentration found in the CSF, have opposing effects on glucose metabolism. Adiponectin enhanced glucose uptake, glycolytic rate, and ATP production through an AMP-activated protein kinase (AMPK)-dependent mechanism; inhibiting AMPK abrogated the effects of adiponectin on glucose uptake and utilization. In contrast, resistin reduced glucose uptake, glycolytic rate, and ATP production, in part, by inhibiting hexokinase (HK) activity in hippocampal neurons. These data suggest that altered CNS levels of adipokines in the context of obesity may impact glucose metabolism in hippocampal neurons, brain region involved in learning and memory functions.

Increased adiponectin is associated with cerebral white matter lesions in the elderly with cognitive impairment

Adiponectin is an adipocyte-derived peptide that increases with age and is thought to protect against atherosclerotic vascular changes and organ damage. However, paradoxically, higher adiponectin levels are associated with increased risk for cardiovascular events and mortality. We investigated whether this adiponectin paradox occurs in elderly people with cognitive impairment. Fifty-two elderly participants with mild cognitive impairment or dementia (20 male and 32 female, aged 60-93 years, mean 80.0) were recruited. We evaluated serum adiponectin levels and cerebral white matter lesions (WML), which are involved in cognitive decline and dementia, by computed tomography. Body mass index (BMI), Mini-Mental State Examination score, history of hypertension (HT), chronic kidney disease, and diabetes mellitus were also assessed. Stepwise multiple regression analysis was used to reveal the relationships between serum adiponectin and age, sex, BMI, HT, diabetes mellitus, chronic kidney disease, Mini-Mental State Examination, and WML scores. High serum adiponectin levels correlated with more severe WML (P = 0.013). Low BMI (P < 0.001), female sex (P = 0.025), and high WML scores (P = 0.039) were significant determinants of high serum adiponectin. HT (P = 0.032) and high adiponectin levels (P = 0.021) were independent risk factors for WML. Overall, we observed an association between serum adiponectin levels and WML severity in elderly people with cognitive decline. Our findings reveal that the adiponectin paradox occurs in this population, and this study may help guide future treatments for elderly people with mild cognitive impairment or dementia.

Serum levels of C1q/tumor necrosis factor-related protein-1 in children with Kawasaki disease

BackgroundTo investigate the serum C1q/tumor necrosis factor-related protein-1 (CTRP1) levels in children with acute Kawasaki disease (KD), as well as the relationship between CTRP1 levels and laboratory variables.MethodsEighty-seven children with KD and 38 healthy controls (HCs) were included in this study. General characteristics were obtained from all subjects. Serum CTRP1 levels in all subjects and serum tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) levels in KD patients were measured using enzyme-linked immunosorbent assay.ResultsCompared with the HC group, serum CTRP1 levels were significantly elevated in the KD group. Significantly higher serum TNF-α, IL-1β, IL-6, and CTRP1 levels were observed in patients with KD with coronary artery lesions (KD-CALs) than in patients with KD without CALs (KD-NCALs). Serum CTRP1 levels were positively correlated with white blood cell counts (WBC), percentage of neutrophils (N%), thrombin time (TT), procalcitonin (Pct), TNF-α, IL-1β, and IL-6 levels. Meanwhile, CTRP1 levels were negatively correlated with the percentage of leukomonocytes (L%) in KD patients. Furthermore, serum CTRP1 levels were positively correlated with the time point of intravenous immunoglobulin (IVIG), WBC, N%, TNF-α, IL-1β, and IL-6 levels in the KD-CAL group.ConclusionCTRP1 may participate in the process of vasculitis and blood coagulation during the acute phase of KD.

Traveling from the hypothalamus to the adipose tissue: The thermogenic pathway

Brown adipose tissue (BAT) is a specialized tissue critical for non-shivering thermogenesis producing heat through mitochondrial uncoupling; whereas white adipose tissue (WAT) is responsible of energy storage in the form of triglycerides. Another type of fat has been described, the beige adipose tissue; this tissue emerges in existing WAT depots but with thermogenic ability, a phenomenon known as browning. Several peripheral signals relaying information about energy status act in the brain, particularly the hypothalamus, to regulate thermogenesis in BAT and browning of WAT. Different hypothalamic areas have the capacity to regulate the thermogenic process in brown and beige adipocytes through the sympathetic nervous system (SNS). This review discusses important concepts and discoveries about the central control of thermogenesis as a trip that starts in the hypothalamus, and taking the sympathetic roads to reach brown and beige fat to modulate thermogenic functions.

Assessing the Functional Role of Leptin in Energy Homeostasis and the Stress Response in Vertebrates

Leptin is a pleiotropic hormone that plays a critical role in regulating appetite, energy metabolism, growth, stress, and immune function across vertebrate groups. In mammals, it has been classically described as an adipostat, relaying information regarding energy status to the brain. While retaining poor sequence conservation with mammalian leptins, teleostean leptins elicit a number of similar regulatory properties, although current evidence suggests that it does not function as an adipostat in this group of vertebrates. Teleostean leptin also exhibits functionally divergent properties, however, possibly playing a role in glucoregulation similar to what is observed in lizards. Further, leptin has been recently implicated as a mediator of immune function and the endocrine stress response in teleosts. Here, we provide a review of leptin physiology in vertebrates, with a particular focus on its actions and regulatory properties in the context of stress and the regulation of energy homeostasis.

C1q/Tumor Necrosis Factor-Related Protein-3 Attenuates Brain Injury after Intracerebral Hemorrhage via AMPK-Dependent Pathway in Rat

C1q/tumor necrosis factor (TNF)-related protein-3 (CTRP3) is a recently discovered adiponectin paralog with established metabolic regulatory properties. However, the role of CTRP3 in intracerebral hemorrhage (ICH) is still mostly unresolved. The aim of the present report was to explore the possible neuroprotective effect of CTRP3 in an ICH rat model and to elucidate the fundamental mechanisms. ICH was induced in rats by intracerebral infusion of autologous arterial blood. The effects of exogenous CTRP3 (recombinant or lentivirus CTRP3) on brain injury were explored on day 7. Treatment with CTRP3 reduced brain edema, protected against disruption of the blood-brain barrier (BBB), improved neurological functions and promoted angiogenesis. Furthermore, CTRP3 greatly intensified phosphorylation of AMP-activated protein kinase (AMPK) in addition to expression of hypoxia inducing factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Finally, the protective effects of CTRP3 could be blocked by either AMPK or VEGF inhibitors. Our findings give the first evidence that CTRP3 is a new proangiogenic and neuroprotective adipokine, which may exert its protective effects at least partly through an AMPK/HIF-1α/ VEGF-dependent pathway, and suggest that CTRP3 may provide a new therapeutic strategy for ICH.

FNDC5 expression and circulating irisin levels are modified by diet and hormonal conditions in hypothalamus, adipose tissue and muscle

Irisin is processed from fibronectin type III domain-containing protein 5 (FNDC5). However, a controversy exists concerning irisin origin, regulation and function. To elucidate the relationship between serum irisin and FNDC5 mRNA expression levels, we evaluated plasma irisin levels and FNDC5 gene expression in the hypothalamus, gastrocnemius muscle and different depots of adipose tissue in models of altered metabolism. In normal rats, blood irisin levels diminished after 48-h fast and with leptin, insulin and alloxan treatments, and serum irisin concentrations increased in diabetic rats after insulin treatment and acute treatments of irisin increased blood insulin levels. No changes were observed during long-term experiments with different diets. We suggested that levels of circulating irisin are the result of the sum of the irisin produced by different depots of adipose tissue and skeletal muscle. This study shows for the first time that there are differences in FNDC5 expression depending on white adipose tissue depots. Moreover, a considerable decrease in visceral and epididymal adipose tissue depots correlated with increased FNDC5 mRNA expression levels, probably in an attempt to compensate the decrease that occurs in their mass. Hypothalamic FNDC5 expression did not change for any of the tested diets but increased with leptin, insulin and metformin treatments suggesting that the regulation of central and peripheral FNDC5/irisin expression and functions are different.

Role of Leptin Deficiency, Inefficiency, and Leptin Receptors in Obesity

Leptin protein consists of 167 amino acids, which is mainly secreted from the white adipose tissue. This protein acts on the hypothalamic regions of the brain which control eating behavior, thus playing a significant role in maintaining body's metabolism. Leptin receptors belong to glycoprotein 130 (gp130) family of cytokine receptors and exist in six isoforms (LEPR a-f), and all the isoforms are encoded by LEPR gene; out of these isoforms, the LEPR-b receptor is the 'longest form,' and in most of the cases, mutations in this isoform cause severe obesity. Also, mutations in the leptin gene (LEP) or its receptors gene can lead to obesity. Some biochemical pathways affect the bioactivity of leptin and/or its receptors. To date, eleven pathogenic mutations have been reported in the LEP which are p.L72S, p.N103K, p.R105W, p.H118L, p.S141C, p.W121X c.104_106delTCA, c.135del3bp, c.398delG, c.481_482delCT, and c.163C>T. Different mutations in the LEPR have also been reported as c.2396-1 G>T, c.1675 G>A, p.P316T, etc. In some studies, where leptin was deficient, leptin replacement therapy has shown positive impact by preventing weight gain and obesity.

CSF and plasma adipokines after tonic-clonic seizures

PURPOSE

Adipokines, especially leptin and adiponectin, have gained increasing importance in pathophysiology of various neurological diseases including epilepsy. There are experimental data suggesting a role for leptin in the genesis of seizures and neuroprotection related to seizures. However there are no clinical studies on the effects of epileptic seizures on adipokines.

METHODS

We measured cerebrospinal fluid (CSF) and plasma levels of leptin, adiponectin and adipsin after provoked or unprovoked primary or secondarily generalized tonic-clonic seizures in 13 female patients and seven controls. The samples were taken within 24h after the seizure onset.

RESULTS

Leptin plasma levels correlated negatively with the time to sample withdrawal, i.e. the longer the time interval between the seizure and the sample the lower the leptin levels in the patients. Interestingly, plasma adiponectin levels were significantly increased after the seizure episode.

CONCLUSION

This study provides further evidence that there are seizure-induced acute changes in adipokine metabolism. Leptin concentrations seem to decrease during the first 24h after the seizure whereas adiponectin levels increase. The meaning of this response is far from clear, but it might be an endogenous attempt to prevent harmful effects of epileptic seizures in the central nervous system.

Linear and undulating periodized strength plus aerobic training promote similar benefits and lead to improvement of insulin resistance on obese adolescents

The present study compares the effectiveness of three types of physical training for obesity control in adolescents submitted to a long-term interdisciplinary therapy. Forty-five post-puberty obese adolescents (15-18yo) were randomly placed in three different groups of physical trainings: aerobic training (AT n=20), aerobic plus strength training with linear periodization (LP n=13) and aerobic plus strength training with daily undulating periodization (DUP n=12). The body composition was evaluated by air-displacement plethysmography; the rest metabolic rate was measured by indirect calorimetry; serum analysis was collected after an overnight fasting. The most important finding of this study was that both LP and DUP groups improved lipid profile, insulin sensitivity and adiponectin concentration (p<0.01). The linear regression showed a negative association between delta (%) adiponectin and delta (%) insulin (p<0.05). Each group presented a significant reduction in body mass, body mass index and fat mass (kg) after short and long-term intervention (p<0.01). However, the AT group reduced the fat-free mass after short-term intervention (p<0.01) and enhanced protein oxidation (p<0.01), whereas only LP group was able to increase the fat-free mass and maintain the rest metabolic rate (RMR). There was a negative correlation between percentage of protein oxidation and RMR (r=-0.75) in all groups. The interdisciplinary therapy models that included aerobic plus strength training were more effective than only aerobic training to improve lipid profile and insulin sensitivity, as well as the inflammatory state by increasing adiponectin. In all groups were observed an improvement on anthropometric profile.

Obesity and coronary microvascular disease - implications for adipose tissue-mediated remote inflammatory response

It is believed that obesity has detrimental effects on the coronary circulation. These include immediate changes in coronary arterial vasomotor responsiveness and the development of occlusive large coronary artery disease. Despite its critical role in regulating myocardial perfusion, the altered behavior of coronary resistance arteries, which gives rise to coronary microvascular disease (CMD) is poorly understood in obesity. A chronic, low-grade vascular inflammation has been long considered as one of the main underlying pathology behind CMD. The expanded adipose tissue and the infiltrating macrophages are the major sources of pro-inflammatory mediators that have been implicated in causing inadequate myocardial perfusion and, in a long term, development of heart failure in obese patients. Much less is known the mechanisms regulating the release of these cytokines into the circulation that enable them to exert their remote effects in the coronary microcirculation. This mini review aims to examine recent studies describing alterations in the vasomotor function of coronary resistance arteries and the role of adipose tissue-derived pro-inflammatory cytokines and adipokines in contributing to CMD in obesity. We provide examples of regulatory mechanisms by which adipokines are released from adipose tissue to exert their remote inflammatory effects on coronary microvessels. We identify some of the important challenges and opportunities going forward.

A leptin-mediated central mechanism in analgesia-enhanced opioid reward in rats

Opioid analgesics are commonly used in chronic pain management despite a potential risk of rewarding. However, it remains unclear whether opioid analgesia would enhance the opioid rewarding effect thereby contributing to opioid rewarding. Utilizing a rat paradigm of conditioned place preference (CPP) combined with ankle monoarthritis as a condition of persistent nociception, we showed that analgesia induced by either morphine or the nonsteroid anti-inflammatory drug ibuprofen increased CPP scores in arthritic rats, suggesting that analgesia itself had a rewarding effect. However, arthritic rats exhibited a significantly higher CPP score in response to morphine than ibuprofen. Thus, the rewarding effect of morphine was enhanced in the presence of persistent nociception, producing a phenomenon of analgesia-enhanced opioid reward. At the cellular level, administration of morphine activated a cascade of leptin expression, glial activation, and dopamine receptor upregulation in the nucleus accumbens (NAc), while administration of ibuprofen decreased glial activation with no effect on leptin expression in the NAc. Furthermore, the morphine rewarding effect was blocked in leptin deficient ob/ob mice or by neutralizing leptin or interleukin-1β in the NAc without diminishing morphine analgesia. The data indicate that systemic opioid can activate a leptin-mediated central mechanism in the NAc that led to the enhanced opioid rewarding effect. These findings provide evidence for an interaction between opioid analgesia and opioid rewarding, which may have implications in clinical opioid dose escalation in chronic pain management.

Spinal leptin contributes to the development of morphine antinociceptive tolerance by activating the STAT3-NMDA receptor pathway in rats

Leptin, an adipokine synthesized mainly by non‑neuronal tissues, has been reported to contribute to the pathogenesis of neuropathic pain. It has been hypothesized that morphine tolerance and neuropathic pain share some common pathological mechanisms. The present study was designed to examine whether spinal leptin is implicated in the development of morphine antinociceptive tolerance, and whether spinal leptin induces the activation of signal transducer and activator of transcription 3 (STAT3) signaling pathway and the NR1 subunit of N‑methyl‑D‑aspartate (NMDA) receptor, in morphine antinociceptive tolerance in rats. The results demonstrated that intrathecal (i.t.) administration of a leptin antagonist (LA) prevented the development of morphine antinociceptive tolerance in rats. Further studies revealed that the levels of the spinal leptin and the leptin receptor (Ob‑R) were time‑dependently increased following chronic morphine treatment. Mechanistic examination indicated that chronic morphine triggered activation of the STAT3 pathway and an increase in the expression of the NR1 subunit of the NMDA receptor, which was ameliorated by i.t. administration of AG490 [a Janus kinase (JAK)‑STAT inhibitor]. The increased activation of STAT3 and the NR1 subunit was markedly attenuated by i.t. treatment with LA. In addition, the spinal administration of AG490 or MK‑801 (a non‑competitive NMDA receptor inhibitor) blocked the development of morphine antinociceptive tolerance. Taken together, these results have demonstrated, for the first time, to the best of our knowledge, that spinal leptin contributes to the development of morphine antinociceptive tolerance by activating the spinal STAT3‑NMDA receptor pathway.

Perturbation of hypothalamic microRNA expression patterns in male rats after metabolic distress: impact of obesity and conditions of negative energy balance

The hypothalamus plays a crucial role in body weight homeostasis through an intricate network of neuronal circuits that are under the precise regulation of peripheral hormones and central transmitters. Although deregulated function of such circuits might be a major contributing factor in obesity, the molecular mechanisms responsible for the hypothalamic control of energy balance remain partially unknown. MicroRNAs (miRNAs) have been recognized as key regulators of different biological processes, including insulin sensitivity and glucose metabolism. However, the roles of miRNA pathways in the control of metabolism have been mostly addressed in peripheral tissues, whereas the potential deregulation of miRNA expression in the hypothalamus in conditions of metabolic distress remains as yet unexplored. In this work, we used high-throughput screening to define to what extent the hypothalamic profiles of miRNA expression are perturbed in two extreme conditions of nutritional stress in male rats, namely chronic caloric restriction and high-fat diet-induced obesity. Our analyses allowed the identification of sets of miRNAs, including let-7a, mir-9*, mir-30e, mir-132, mir-145, mir-200a, and mir-218, whose expression patterns in the hypothalamus were jointly altered by caloric restriction and/or a high-fat diet. The predicted targets of these miRNAs include several elements of key inflammatory and metabolic pathways, including insulin and leptin. Our study is the first to disclose the impact of nutritional challenges on the hypothalamic miRNA expression profiles. These data will help to characterize the molecular miRNA signature of the hypothalamus in extreme metabolic conditions and pave the way for targeted mechanistic analyses of the involvement of deregulated central miRNAs pathways in the pathogenesis of obesity and related disorders.

Adiponectin as a new paradigm for approaching Alzheimer's disease

Adiponectin is an adipocytokine released by the adipose tissue and has multiple roles in the immune system and in the metabolic syndromes such as cardiovascular disease, Type 2 diabetes, obesity and also in the neurodegenerative disorders including Alzheimer's disease. Adiponectin regulates the sensitivity of insulin, fatty acid catabolism, glucose homeostasis and anti-inflammatory system through various mechanisms. Previous studies demonstrated that adiponectin modulates memory and cognitive impairment and contributes to the deregulated glucose metabolism and mitochondrial dysfunction observed in Alzheimer's disease. Here, we aim to summarize recent studies that suggest the potential correlation between adiponectin and Alzheimer's disease.

Heterozygosity for leptin receptor (fa) accelerates hepatic triglyceride accumulation without hyperphagia in Zucker rats

SUMMARY

Leptin, ob gene product, and its receptors are involved in the regulation of peripheral lipid and glucose metabolism. The present study sought to clarify the functional role of peripheral leptin receptors in hepatic lipid metabolism through analysis of Zucker rats (fa/fa, +/fa), as complete or partial leptin receptor insufficiency models, respectively. In Zucker fa/fa rats, calorie intake, body weight, liver weight, hepatic triglyceride content and serum insulin, triglycerides, FFA, and leptin were elevated compared to lean littermates (+/+ rats). In contrast, Zucker +/fa rats showed no remarkable changes in calorie intake, body weight and serum FFA compared with +/+ rats. Nevertheless, hepatic triglyceride content, liver weight and other serum parameters such as insulin, triglyceride and leptin were higher than in +/+ rats. In the representation of fatty acids component in the liver, there were no changes in +/fa rats relative to +/+ rats. Thus, in Zucker +/fa rats, fatty liver may develop in the absence of hyperphagia, obesity or changes in hepatic fatty acid metabolism. These results indicate that partial insufficiency of leptin receptor rather than changes in serum insulin, triglyceride and leptin may contribute to the increase in hepatic triglyceride content observed in +/fa rats.:

Adipose tissue, diet and aging

Age related increase in body fat mass, visceral adipose tissue (AT), and ectopic fat deposition are strongly related to worse health conditions in the elderly. Moreover, with aging higher inflammation in adipose tissue may be observed and may contribute to inflammaging. Aging may significantly affect AT function by modifying the profile of adipokines produced by adipose cells, reducing preadipocytes number and their function and increasing AT macrophages infiltration. The initiating events of the inflammatory cascade promoting a greater AT inflammatory profile are not completely understood. Nutrients may determine changes in the amount of body fat, in its distribution as well as in AT function with some nutrients showing a pro-inflammatory effect on AT. Evidences are sparse and quite controversial with only a few studies performed in older subjects. Different dietary patterns are the result of the complex interaction of foods and nutrients, thus more studies are needed to evaluate the association between dietary patterns and changes in adipose tissue structure, distribution and function in the elderly.

Novel drug-regulated transcriptional networks in brain reveal pharmacological properties of psychotropic drugs

Background

Despite their widespread use, the biological mechanisms underlying the efficacy of psychotropic drugs are still incompletely known; improved understanding of these is essential for development of novel more effective drugs and rational design of therapy. Given the large number of psychotropic drugs available and their differential pharmacological effects, it would be important to establish specific predictors of response to various classes of drugs.

Results

To identify the molecular mechanisms that may initiate therapeutic effects, whole-genome expression profiling (using 324 Illumina Mouse WG-6 microarrays) of drug-induced alterations in the mouse brain was undertaken, with a focus on the time-course (1, 2, 4 and 8 h) of gene expression changes produced by eighteen major psychotropic drugs: antidepressants, antipsychotics, anxiolytics, psychostimulants and opioids. The resulting database is freely accessible at http://www.genes2mind.org. Bioinformatics approaches led to the identification of three main drug-responsive genomic networks and indicated neurobiological pathways that mediate the alterations in transcription. Each tested psychotropic drug was characterized by a unique gene network expression profile related to its neuropharmacological properties. Functional links that connect expression of the networks to the development of neuronal adaptations (MAPK signaling pathway), control of brain metabolism (adipocytokine pathway), and organization of cell projections (mTOR pathway) were found.

Conclusions

The comparison of gene expression alterations between various drugs opened a new means to classify the different psychoactive compounds and to predict their cellular targets; this is well exemplified in the case of tianeptine, an antidepressant with unknown mechanisms of action. This work represents the first proof-of-concept study of a molecular classification of psychoactive drugs.

Neuroendocrine and cardiac metabolic dysfunction and NLRP3 inflammasome activation in adipose tissue and pancreas following chronic spinal cord injury in the mouse

CVD (cardiovascular disease) represents a leading cause of mortality in chronic SCI (spinal cord injury). Several component risk factors are observed in SCI; however, the underlying mechanisms that contribute to these risks have not been defined. Central and peripheral chronic inflammation is associated with metabolic dysfunction and CVD, including adipokine regulation of neuroendocrine and cardiac function and inflammatory processes initiated by the innate immune response. We use female C57 Bl/6 mice to examine neuroendocrine, cardiac, adipose and pancreatic signaling related to inflammation and metabolic dysfunction in response to experimentally induced chronic SCI. Using immuno-histochemical, -precipitation, and -blotting analysis, we show decreased POMC (proopiomelanocortin) and increased NPY (neuropeptide-Y) expression in the hypothalamic ARC (arcuate nucleus) and PVN (paraventricular nucleus), 1-month post-SCI. Long-form leptin receptor (Ob-Rb), JAK2 (Janus kinase)/STAT3 (signal transducer and activator of transcription 3)/p38 and RhoA/ROCK (Rho-associated kinase) signaling is significantly increased in the heart tissue post-SCI, and we observe the formation and activation of the NLRP3 (NOD-like receptor family, pyrin domain containing 3) inflammasome in VAT (visceral adipose tissue) and pancreas post-SCI. These data demonstrate neuroendocrine signaling peptide alterations, associated with central inflammation and metabolic dysfunction post-SCI, and provide evidence for the peripheral activation of signaling mechanisms involved in cardiac, VAT and pancreatic inflammation and metabolic dysfunction post-SCI. Further understanding of biological mechanisms contributing to SCI-related inflammatory processes and metabolic dysfunction associated with CVD pathology may help to direct therapeutic and rehabilitation countermeasures.

[Adipokines in healthy and obese children]

The worldwide increase in the prevalence of obesity in children and adolescents during the last decades, as well as the mounting evidence indicating that obesity is associated with an increased incidence of comorbidities and the risk of premature death, resulting in a high economic impact, has stimulated obesity focused research. These studies have highlighted the prominent endocrine activity of adipose tissue, which is exerted through the synthesis and secretion of a wide variety of peptides and cytokines, called adipokines. This review presents a summary of the current knowledge and most relevant studies of adipokine dynamics and actions in children, focusing on the control of energy homeostasis, metabolic regulation (particularly carbohydrate metabolism), and inflammation. The particularities of adipose secretion and actions in healthy children, from birth to adolescence, and the modifications induced by early onset obesity are highlighted.

Adipokines in childhood obesity

The worldwide increase in the prevalence of obesity in children and adolescents during the past decades, in addition to mounting evidence indicating that obesity is associated with an increased incidence of comorbidities and the risk of premature death, resulting in a high economical impact, has stimulated obesity-focused research. These studies have highlightened the prominent endocrine activity of adipose tissue, which is exerted through the synthesis and secretion of a wide variety of peptides and cytokines, called adipokines. In the present review, we have summarized the current knowledge and most relevant studies of adipokine dynamics and actions in children, focusing on the control of energy homeostasis, metabolic regulation (particularly, carbohydrate metabolism), and inflammation. The particularities of adipose secretion and actions in healthy children, from birth to adolescence, and the modifications induced by early-onset obesity are highlighted.

Association between novel adipocytokines adiponectin, vaspin, visfatin, and thyroid: An experimental and clinical update

Adipose tissue secretes a variety of active biological substances, called adipocytokines, that act in an autocrine, paracrine, and endocrine manner. They have roles in appetite control, thermogenesis, and thyroid and reproductive functions. All these molecules may lead to local and generalized inflammation, mediating obesity-associated vascular disorders including hypertension, diabetes, atherosclerosis, and insulin resistance. Thyroid dysfunction is associated with changes in body weight, thermogenesis, and energy expenditure. The connections between cardiovascular risk factors such as dyslipidemia, impaired glucose tolerance, insulin resistance, atherosclerosis, and thyroid dysfunction have been reported in several studies. The adipocytokines serve as causative or protective factors in the development of these disorders in the states of thyroid dysfunction. Abnormal levels of adipocytokines (adiponectin (ADP), leptin, resistin, vaspin, and visfatin) in hypo- and hyperthyroidism have been reported with controversial results. This review aims to update the implication of novel adipokines ADP, vaspin, and visfatin in thyroid dysfunction.

Weight-loss diet alone or combined with progressive resistance training induces changes in association between the cardiometabolic risk profile and abdominal fat depots

BACKGROUND/AIMS

A weight-loss diet alone or combined with a progressive resistance training program induced different adaptations on cardiometabolic risk, i.e. regional changes in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) volume distribution patterns. We hypothesized that a heterogeneous adipose tissue metabolism may exist between visceral fat at different discal levels.

METHODS

Thirty-four obese women, aged 40-60 years, were randomized to three groups: a control group (n = 9), a diet group (WL; n = 12) with a caloric restriction of 500 kcal/day during 16 weeks, or a diet-plus-resistance-training group (WL+RT; n = 13) with the same caloric restriction and a 16-week resistance training of 2 sessions per week.

RESULTS

The association pattern between abdominal fat depots and glucose metabolism variables showed a change from the L4-L5 region (preintervention) to VAT L2-L3 and SAT L2-L3 in the WL and WL+RT groups, respectively. It is noteworthy that accumulation of fat in the midthigh was not characterized by a more favorable lipid profile or glucose metabolism.

CONCLUSION

Our results reinforce the importance of considering L2-L3 images to predict insulin resistance after a weight-loss diet, alone or combined with resistance training.

Functional and structural features of adipokine family

In the mid-1990s, the interest in adipose tissue was revived by the discovery of leptin. Since then numerous other hormones have been isolated from white adipose tissue that has no longer considered an inert tissue mainly devoted to energy storage but emerged as an active participant in regulating physiologic and pathologic processes, including immunity and inflammation. Adipose tissue produces and releases a variety of proinflammatory and anti-inflammatory factors, including the adipokines, as well as cytokines and chemokines. Proinflammatory molecules produced by adipose tissue have been implicated as active participants in the development of insulin resistance and the increased risk of cardiovascular disease associated with obesity. In contrast, reduced leptin levels might predispose to increased susceptibility to infection caused by reduced T-cell responses in malnourished individuals. Altered adipokine levels have been observed in a variety of inflammatory conditions, although their pathogenic role has not been completely clarified. In this paper we want to review: (i) the role of adipose tissue in different biological processes, (ii) the functional and structural description of all the known adipokines subdivided in different subfamilies, (iii) the adipokine involvement in obesity and cancers, and (iv) the adipokine interactome.

Energy expenditure and bone formation share a common sensitivity to AP-1 transcription in the hypothalamus

The regulation of bone and fat homeostasis and its relationship to energy expenditure has recently been the focus of increased attention because of its potential relevance to osteoporosis, obesity, and diabetes. Although central effectors within the hypothalamus have been shown to contribute to the regulation of both energy balance and bone homeostasis, little is known of the underlying mechanisms, including the possible involvement of transcriptional factors within the hypothalamus. Transgenic mice overexpressing ΔFosB, a splice variant of the AP-1 transcription factor FosB with mixed agonist-antagonistic properties, have increased energy expenditure and bone mass. Because these mice express ΔFosB in bone, fat, and hypothalamus, we sought to determine 1) whether overexpression of ΔFosB within the hypothalamus was sufficient to regulate energy expenditure and whether it would also regulate bone mass, and 2) whether these effects were the result of antagonism to AP-1. Our results show that stereotactic injection of an adeno-associated virus vector to restrict overexpression of ΔFosB to the ventral hypothalamus of wild-type mice induced a profound increase in both energy expenditure and bone formation and bone mass. This effect was phenocopied, at an even stronger level, by overexpression of a dominant-negative DNJunD, a pure AP-1 antagonist. Taken together, these results suggest that downregulation of AP-1 activity in the hypothalamus profoundly increases energy expenditure and bone formation, leading to both a decrease in adipose mass and an increase in bone mass. These findings may have physiological implications because ΔFosB is expressed and regulated in the hypothalamus.

Alterations in mouse hypothalamic adipokine gene expression and leptin signaling following chronic spinal cord injury and with advanced age

Chronic spinal cord injury (SCI) results in an accelerated trajectory of several cardiovascular disease (CVD) risk factors and related aging characteristics, however the molecular mechanisms that are activated have not been explored. Adipokines and leptin signaling are known to play a critical role in neuro-endocrine regulation of energy metabolism, and are now implicated in central inflammatory processes associated with CVD. Here, we examine hypothalamic adipokine gene expression and leptin signaling in response to chronic spinal cord injury and with advanced age. We demonstrate significant changes in fasting-induced adipose factor (FIAF), resistin (Rstn), long-form leptin receptor (LepRb) and suppressor of cytokine-3 (SOCS3) gene expression following chronic SCI and with advanced age. LepRb and Jak2/stat3 signaling is significantly decreased and the leptin signaling inhibitor SOCS3 is significantly elevated with chronic SCI and advanced age. In addition, we investigate endoplasmic reticulum (ER) stress and activation of the uncoupled protein response (UPR) as a biological hallmark of leptin resistance. We observe the activation of the ER stress/UPR proteins IRE1, PERK, and eIF2alpha, demonstrating leptin resistance in chronic SCI and with advanced age. These findings provide evidence for adipokine-mediated inflammatory responses and leptin resistance as contributing to neuro-endocrine dysfunction and CVD risk following SCI and with advanced age. Understanding the underlying mechanisms contributing to SCI and age related CVD may provide insight that will help direct specific therapeutic interventions.

Inflammatory cause of metabolic syndrome via brain stress and NF-κB

Metabolic syndrome, a network of medical disorders that greatly increase the risk for developing metabolic and cardiovascular diseases, has reached epidemic levels in many areas of today's world. Despite this alarming medicare situation, scientific understandings on the root mechanisms of metabolic syndrome are still limited, and such insufficient knowledge contributes to the relative lack of effective treatments or preventions for related diseases. Recent interdisciplinary studies from neuroendocrinology and neuroimmunology fields have revealed that overnutrition can trigger intracellular stresses to cause inflammatory changes mediated by molecules that control innate immunity. This type of nutrition-related molecular inflammation in the central nervous system, particularly in the hypothalamus, can form a common pathogenic basis for the induction of various metabolic syndrome components such as obesity, insulin resistance, and hypertension. Proinflammatory NF-κB pathway has been revealed as a key molecular system for pathologic induction of brain inflammation, which translates overnutrition and resulting intracellular stresses into central neuroendocrine and neural dysregulations of energy, glucose, and cardiovascular homeostasis, collectively leading to metabolic syndrome. This article reviews recent research advances in the neural mechanisms of metabolic syndrome and related diseases from the perspective of pathogenic induction by intracellular stresses and NF-κB pathway of the brain.

Beneficial effects of rosuvastatin on insulin resistance, adiposity, inflammatory markers and non-alcoholic fatty liver disease in mice fed on a high-fat diet

The aim of the present study was to evaluate the effects of ST (rosuvastatin) and GZ (rosiglitazone) on IR (insulin resistance) and on liver as well as adipose tissue in mice fed on an HF (high-fat) diet. Our data show that treatment with ST resulted in a marked improvement in insulin sensitivity characterized by enhanced glucose clearance during the insulin tolerance test and a 70% decrease in the HOMA-IR (homoeostasis model assessment of insulin resistance) index level (P=0.0008). The ST-treated mice exhibited lower gains in BM (body mass; -8%; P<0.01) and visceral fat pad thickness (-60%; P<0.01) compared with the untreated HF group. In comparison with HF-diet-fed mice, HF+ST-treated mice showed a significant reduction in hepatomegaly and liver steatosis (-6%, P<0.05; and -21%, P<0.01 respectively). In HF+ST-treated mice, the hepatic TAG (triacylglycerol) levels were reduced by 58% compared with the HF group (P<0.01). In addition, the expression of SREBP-1c (sterol-regulatory-element-binding protein-1c) was decreased by 50% in the livers of HF+ST-treated mice (P<0.01) relative to the HF-diet-fed mice. The levels of resistin were lower in the HF+ST-treated group compared with the HF group (44% less, P< 0.01). In conclusion, we demonstrated that ST treatment improved insulin sensitivity and decreased liver steatosis in mice fed on an HF diet. Furthermore, ST reduced BM gains, improved the circulating levels of plasma cholesterol and TAG, and reduced hepatic TAG, which was concomitant with lower resistin levels.

Experimental hyperthyroidism decreases gene expression and serum levels of adipokines in obesity

Aims. To analyze the influence of hyperthyroidism on the gene expression and serum concentration of leptin, resistin, and adiponectin in obese animals. Main Methods. Male Wistar rats were randomly divided into two groups: control (C)—fed with commercial chow ad libitum—and obese (OB)—fed with a hypercaloric diet. After group characterization, the OB rats continued receiving a hypercaloric diet and were randomized into two groups: obese animals (OB) and obese with 25 μg triiodothyronine (T₃)/100 BW (OT). The T₃ dose was administered every day for the last 2 weeks of the study. After 30 weeks the animals were euthanized. Samples of blood and adipose tissue were collected for biochemical and hormonal analyses as well as gene expression of leptin, resistin, and adiponectin. Results. T₃ treatment was effective, increasing fT₃ levels and decreasing fT₄ and TSH serum concentration. Administration of T₃ promotes weight loss, decreases all fat deposits, and diminishes serum levels of leptin, resistin, and adiponectin by reducing their gene expression. Conclusions. Our results suggest that T₃ modulate serum and gene expression levels of leptin, resistin, and adiponectin in experimental model of obesity, providing new insights regarding the relationship between T₃ and adipokines in obesity.